import 'dart:io';

const int minTemp = 15;
const int maxTemp = 30;

void main() {
  bool lightsOn = false;
  int thermostat = 20;
  bool securityArmed = false;

  print('Welcome to the Smart Home System!');

  while (true) {
    print('\nPlease choose an action:');
    print('1. Toggle lights');
    print('2. Set thermostat temperature');
    print('3. Arm/disarm security system');
    print('4. View system status');
    print('5. Exit');

    stdout.write('Enter your choice: ');
    String? choiceInput = stdin.readLineSync();

    if (choiceInput == null || choiceInput.trim().isEmpty) {
      print('Invalid input. Please try again.');
      continue;
    }

    int? choice = int.tryParse(choiceInput.trim());
    if (choice == null) {
      print('Please enter a valid number.');
      continue;
    }

    if (choice == 5) {
      print('Exiting the system. Goodbye!');
      break;
    }

    switch (choice) {
      case 1:
        lightsOn = !lightsOn;
        print('Lights are now ${lightsOn ? "ON" : "OFF"}.');
        break;

      case 2:
        bool validTemp = false;
        while (!validTemp) {
          stdout.write('Set thermostat ($minTemp-$maxTemp): ');
          String? tempInput = stdin.readLineSync();
          if (tempInput != null) {
            int? temp = int.tryParse(tempInput.trim());
            if (temp != null && temp >= minTemp && temp <= maxTemp) {
              thermostat = temp;
              print('Thermostat set to $temp°C.');
              validTemp = true;
            } else {
              print('Must be $minTemp-$maxTemp.');
            }
          }
        }
        break;

      case 3:
        print('Security: ${securityArmed ? "ARMED" : "DISARMED"}');
        stdout.write('${securityArmed ? "Disarm" : "Arm"}? (y/n): ');
        String? input = stdin.readLineSync();
        if (input != null && input.trim().toLowerCase() == 'y') {
          securityArmed = !securityArmed;
          print('Security now ${securityArmed ? "ARMED" : "DISARMED"}.');
        }
        break;

      case 4:
        String lightsStatus = lightsOn ? 'ON' : 'OFF';
        
        String dayLabel = '';
        if (thermostat % 3 == 0 && thermostat % 5 == 0) {
          dayLabel = 'Perfect Day';
        } else if (thermostat % 3 == 0) {
          dayLabel = 'Cool Day';
        } else if (thermostat % 5 == 0) {
          dayLabel = 'Warm Day';
        }
        
        String thermostatLine = dayLabel.isEmpty ? '$thermostat°C' : '$thermostat°C - $dayLabel';
        String securityStatus = securityArmed ? 'ARMED' : 'DISARMED';

        print('\nSystem Status:');
        print('- Lights: $lightsStatus');
        print('- Thermostat: $thermostatLine');
        print('- Security: $securityStatus');
        break;

      default:
        print('Invalid choice.');
    }
  }
}